1. Field of the Invention
Embodiments of the invention generally relate to archery equipment. More specifically, at least one embodiment, relates to apparatus, system and method for an electronic archery apparatus.
2. Discussion of Related Art
Target archers often use a specialized arrow that is suitable for long distance shooting at which their competition takes place. The arrow (an Easton X-10) has an exceptionally narrow diameter relative to other conventional arrows and can also include a barrel shape where the fore and aft ends have a slightly smaller diameter than a region located somewhere between the ends of the shaft. The X-10 and other narrow diameter arrow shafts employ specialized arrowpoints, and often, unique hardware for attachment of the arrowpoint to the arrow shaft. These narrow diameter shafts are selected by Olympic archers and other competitive target archers because they have a successful track record in competition.
Referring to FIG. 1A, a one piece arrowpoint 10 is illustrated. Arrowpoint 10 includes a tip 12, an extension 14 and two break-off sections 16. The overall mass of the arrowpoint 10 is 120 grains. In a conventional configuration, each of the break-off sections weighs 10 grains. This permits the archer to adjust the weight of the arrowpoint from 120 grains to 100 grains in two 10 grain steps. The arrowpoint 10 is attached to the arrow by inserting the arrowpoint 10 within the hollow cylindrical shaft of the arrow such that the extension 14 and the break-off points are fully located within the arrow shaft and the tip 12 extends forward of the distal end of the arrow shaft. The arrowpoint 10 illustrated in FIG. 1A is constructed of stainless steel. The dimensions and weight that are provided by the arrowpoint 10 result from the density of the stainless steel and the length of each of the sections: the length of the tip 12, the length of the extension 14 and the length of each of the break-off points 16.
In addition to the overall mass, archers using an X-10 arrow often seek an arrowpoint that has a center of mass within a fairly narrow tolerance. In general, the center of mass of the arrowpoints used in Olympic archery is located between approximately the proximate end of the tip 12 and 0.35 inches rear of the proximate end of the tip 12. As should be apparent, the center of mass can shift within the preceding range depending on whether the arrowpoint includes each break-off section, only one break-off section or neither break-off section. In general, however, the change in the center of mass results in the center of mass of the arrowtip 10 staying within the above-mentioned range at or immediately rear of the proximate end of the tip 12 (that is immediately rear of the distal end of the arrow) when the arrowtip 10 is installed in an arrowshaft.
As should be appreciated, the density of the material of the arrowpoint 10 also affects the center of mass. For example, arrowpoints manufactured from tungsten are also a common choice among top target archers. Because tungsten has a significantly higher density than stainless steel, tungsten tips have a reduced overall length and different locations of the center of mass when compared with the stainless steel arrowpoint 10. For example, the lengths of each of the tip 12, the extension 14 and the break-off sections 16 of a 100-120 grain tungsten points have a reduced length relative to the corresponding sections of an arrowpoint manufactured from stainless steel. Here too, however, the center of mass falls within the above-mentioned range for each of the 100, 110 and 120 grain configurations.
Other styles of narrow shaft arrows employ an adapter that allows a threaded attachment of an arrowpoint to the narrow-shaft arrow. Referring to FIG. 1B, one such adapter 20 is illustrated. The adapter 20 includes an insert 22 and an extension 24. The insert 22 can be made of material such as aluminum, brass or steel and includes a threaded region internal to the insert that allows the attachment of an arrowpoint with a threaded shank. The extension 24 is generally made of a hollow aluminum tube that adds weight and, when inserted within the arrow shaft, stiffens the arrow shaft rearward of the insert and the distal end of the arrow shaft.
In practice, the arrowpoint 10 is installed using hot melt glue so that it can later be re-heated and removed from the arrow shaft. For example, extension 14 and break-off sections 16 can be heated, the hot melt can then be applied to the two regions before the arrowpoint 10 is inserted within the hollow-cylindrical arrow shaft. With the arrowpoint 10 fully inserted, the face located at the rear of the tip 12 abuts the forward end of the arrow shaft. To remove the arrowpoint 10, heat is applied to the tip to re-melt the hot melt and allow the extension 14 and break-off sections to be withdrawn from the arrow shaft.
Similarly, the adapter 20 can be glued within the arrow shaft by applying a glue to the extension 24 and the insert and inserting the adapter 20 within the arrow shaft starting with the extension 24 and sliding the adapter within the shaft until the flange 21 abuts the forward end of the shaft. In use, an arrow tip is threaded to the insert 22. To remove the adapter 20, the exposed portion of the arrow tip is heated to re-melt the glue and release the bond between the insert 28 and the extension 24 to allow the adapter 20 to be withdrawn from the shaft.
Referring to FIGS. 9A-9C, a prior art stainless steel arrowpoint 10 is illustrated. Longitudinal dimensions are referenced to a point (x=0) at which the tip 12 abuts the distal end of the arrow shaft when the extension 14 and break-off points 16, if attached, are fully inserted within the arrow shaft. Dimensions to the right of x=0 have positive values while dimensions to the left of x=0 have negative values. FIGS. 9A-9C illustrate that the center of mass ranges from 0.29 inches to −0.04 inches with both break-off sections 16 and no break-off sections, respectively. In general, the preceding illustrates that the center of mass is located substantially from 0.30 inches to 0.0 inches. In addition, FIG. 9B illustrates that a maximum diameter D of the tip 12.
Referring to FIGS. 10A-10C, a prior art tungsten arrowpoint 11 is illustrated. FIGS. 10A-10C illustrate that the center of mass ranges from 0.35 inches to 0.19 inches with both break-off sections 16 and no break-off sections, respectively. In general, the preceding illustrates that the center of mass is located substantially from 0.35 inches to 0.2 inches.
Recently, microelectronic sensing systems have been included in otherwise conventional arrowpoints. These microelectronic systems provide quantified performance feedback that can be used by archers in training to improve the selection and adjustment of their archery equipment, and also to evaluate the archers' form. Such approaches are described in the following applications owned by the assignee of this application: U.S. patent application Ser. No. 12/982,456, entitled “Apparatus, System and Method for Electronic Archery Devices,” filed Dec. 30, 2010; U.S. Pat. No. 8,221,273, entitled “Apparatus, System and Method for Archery Equipment,” issued Jul. 17, 2012; and U.S. Pat. No. 7,972,230, entitled “System and Apparatus for Archery Equipment,” issued Jul. 5, 2011. Each of the preceding patents or patent applications is herein incorporated by reference in its entirety.
The small form factor and specialized nature of the arrowpoints used by target archers and the precise requirements for weight and center of mass create significant barriers to the addition of the microelectronic sensing systems in these arrowpoints. For example, the margin of victory in archery competition is often determined by fractions of an inch following a 50 meter or longer flight of the competitors' arrow. As a result, any electronics added to the arrow must be precisely placed to maintain the flight characteristics as closely as possible to those of the conventional arrow without the sensing system.
Further, conventional arrowpoint construction provides a solid mass that tapers to a point. A solid mass is advantageous for repeated high force target-impacts but is not suitable for integration of electronics. Generally, CNC machining (for example, screw machining) is employed to manufacture arrowpoints suitable for housing electronics. However, these conventional approaches can be challenging and economically impractical to machine tubes that are long enough to house the electronics of an arrowpoint because the tooling must extend down the interior of the tube. In addition, a considerable amount of waste material is produced by such a machining operation.